Turbo is a temporary thing. When the processor thinks it needs to run at the turbo frequency, it will pull more power in order to run at that frequency. The processors and stock coolers are built with this in mind, so they can take the stress of turbo with pretty much no ill effects, since it's only when the CPU really needs it that it runs in turbo (though I've heard that a lot of processors will basically turbo all the time anyways because they can).
Overclocking requires manually adjusting multiplier and voltages and is really requires an aftermarket cooler for best benefits, because running at a speed over stock 24/7 is going to generate more heat.